Germany utility models Nos. 87 14 620 and 74 20 269 already disclose thermometer-watches equipped with liquid crystal temperature indicators.
These liquid crystal indicators comprise a plurality of discret thermochromic sensors, arranged facing a temperature scale, which reflect different coloured light and/or which have a different contrast according to the temperature. The temperature can thus be read directly with the aid of the graduated scale arranged facing the sensors.
A thermometer-watch of this type, however, has the disadvantage of not taking account of the influence of thermal contact with the body of the person wearing it so that the temperature reading obtained is inaccurate when the watch is worn. Indeed, if the temperature of an unworn watch varies linearly in accordance with the temperature of the environment in which it is situated, the same does not apply when the watch is worn. In the latter case, if the ambient temperature is low, the sensors will be at a higher temperature than the ambient temperature because the watch is in direct thermal contact with the body of the wearer, whilst if the ambient temperature is higher than that of the body, the phenomenon is reversed.
To obviate this drawback, there are thermometerwatches having temperature sensors such as thermistors connected to measuring circuits and comprising a switch which can be activated according to whether the user wishes to measure a temperature while the watch is worn or while the watch is not worn.
However, these thermometer watches use complicated electronic corrective circuits and are therefore of a high cost price.
It is thus the main aim of the invention to remedy the drawbacks of the above mentioned prior art by providing a watch comprising an indicating device which allows an exact temperature reading to be given of the environment in which the watch is situated, regardless of whether the watch is worn or not, and to do so in a simple and cost effective manner.